Many Fox Chase Cancer Center (FCCC) studies, including those in cancer control and prevention, translational research, human genetics, behavioral medicine and some animal trials employ a variety of designs that are substantially more complex than typical cancer clinical trials. These investigations require development of study-specific information systems for project management, and the collection, validation, storage, and retrieval of data. The Population Studies Facility (PSF) facilitates research conducted by FCCC peer-reviewed, funded investigators by providing access to a team of information systems professionals with experience in state-of-the-art software engineering applied to cancer research. The PSF functions include development of; databases for the storage and manipulation of large quantities of questionnaire, clinical, molecular and specimen data; electronic data entry and retrieval systems; report generation software; consistency and quality control systems; and systems that provide integration and controlled exchange of data from diverse sources. For example, the system developed by the PSF for the Breast Cancer Family Registry study provides for the entry, coordination and retrieval of longitudinal information, specimen inventory, genetic testing, and complex pedigree data. The PSF also provides systems that facilitate the peer-reviewed, funded investigator support activities of many CCSG-supported cores. The PSF has developed information systems that maintain data on over 180,000 subjects. Of these, more than 60,000 were enrolled in FCCC studies within the US; the remainder participated in several international cohort studies. The PSF provided services to 54 peer-reviewed, funded investigators in all five Programs and 129 projects over the last five years. These represent 35% and 6 1% increases in the number of supported investigators and projects, respectively, over the previous funding cycle. Improved application development efficiency provided by the PSF's creation of the Population Research Application Generation Environment (PRESAGE) toolset and the use of open source solutions has allowed the PSF to accommodate the increase in demand for informatics services with only a 9% increase in staffing. The PSF made contributions to 100 manuscripts and PSF personnel have appeared as co-authors on 47 publications over the current funding period. It has a user charge back system that, combined with other direct grant funding, recoups 74% of its operating cost. In 2009, 66.2% of its use was directly for peer-reviewed, funded investigators. This Facility was rated Outstanding during the last review.